1. Field of the Invention
This invention relates to a solid contact electrical switch, and more particularly to a pushbutton operated switch having a rotating member, sometimes referred to as a "ball point pen" type switch.
2. Description of the Prior Art
Various pushbutton operated switches with rotating members have been used for many years and are well known in the art. These switches are characterized by a pushbutton actuator having cam surfaces which engage corresponding cam followers on a rotating intermediate cam member to produce a rotary motion that is used in a switching mechanism. The resulting action is similar to that of a ball point pen, in that sequentially pushing the pushbutton causes engagement of the rotating member to open and close the switch.
Examples of such switches are shown in the following U.S. Pat. No. 3,204,067, issued to Brown; U.S. Pat. No. 3,223,072, issued to Bross; U.S. Pat. No. 3,402,379, issued to Amis et al.; U.S. Pat. No. 3,523,168, issued to Holmes; U.S. Pat. No. 3,694,603, issued to Congelliere et al.; U.S. Pat. No. 4,175,222, issued to Buttner; U.S. Pat. No. 4,230,921, issued to Wearing et al.; U.S. Pat. No. 4,293,751, issued to Van Benthuysen et al.; U.S. Pat. No. 4,317,015, issued to Buttner et al.; U.S. Pat. No. 4,319,106, issued to Armitage; U.S. Pat. No. 4,463,231, issued to Cooper et al.; U.S. Pat. No. 4,506,124, issued to Rose et al.; U.S. Pat. No. 4,771,141, issued to Flumignan et al.; and U.S. Pat. No. 4,891,476, issued to Nation et al.
These switches employ various designs to utilize the rotational movement of the intermediate rotating cam member to make and brake the contacts. For example, in U.S. Pat. No. 3,204,067, issued to Brown, the conductor which rotates with the cam member rotationally engages fixed contacts mounted in the base. In U.S. Pat. No. 3,523,168, issued to Holmes, the rotating cam member moves a second plunger to accomplish the switching. In U.S. Pat. No. 4,175,222, issued to Buttner, and U.S. Pat. No. 4,317,015, issued to Buttner et al., the rotation of the cam member moves a cylindrical contact member downwardly to move it out of engagement with the fixed contacts. In U.S. Pat. No. 4,293,751, issued to Van Benthuysen et al., the cam member has a drive arm with contactor paddles which rotate with the cam member, and as the arm member rotates, the paddles engage a contact plate fixed in the housing.
In many cases, these types of switches are unsuitable for certain applications due to the manner in which the conductor engages and disengages from the contacts. To produce a more desirable switching action, many switches require multiple springs or complicated mechanisms to enhance the engagement of the bridge conductor with the contacts and to move the conductor away from the contacts so as to reduce heat and erosion as much as possible. Furthermore, these switches should compensate for contact "bounce" which may occur when the contacts move together rapidly.